In order to reduce emissions of carbon dioxide gas as a way to address global warming, there has been increasing development of vehicles configured such that a vehicle-mounted power storage device can be charged from outside, such as electric vehicles and plug-in hybrid vehicles.
Japanese Patent Laying-Open No. 2010-140451 (Patent Document 1) discloses monitoring the approach of an object by a sonar with regard to a charging device for a vehicle-mounted battery in a plug-in hybrid vehicle and an electric vehicle. When an object comes within a prescribed distance, this technique generates a warning signal, issues an audio warning with a horn or a light warning with illumination, starts recording image information from a camera, and communicates with an established mobile network through a vehicle-mounted communication device.